ABSTRACT
A distinct type of multi-solid, highly-saline fluid inclusions (MS-type) is hosted by quartz phenocrysts from Llamo porphyry, Zaldívar Cu-porphyry deposit (Chile). These inclusions homogenize at truly magmatic temperatures (700° to 1000° C), well above the typical “boiling” fluids in Cu-porphyry systems. The combination of PIXE, Raman microanalysis and traditional microthermometry techniques allows nondestructive, in situ analysis of individual MS inclusions, with a good qualitative determination of the composition of trapped fluids. Analytical results indicate that MS inclusions contain complex chlorine brines, in which Na, K, Fe, Cu and Mn are dominant. This fluid most probably play an important role in the separation of metals from the magma, as well as in their later transport and deposition in the Cu-porphyry hydrothermal environment. The high Cu-content of MS inclusions strongly supports magma as the dominant source for this metal (orthomagmatic model), later redistributed by post-magmatic (hydrothermal) processes.
